Organic light-emitting display apparatus and manufacturing method thereof

ABSTRACT

An organic light-emitting display apparatus and a manufacturing method thereof. The organic light-emitting display apparatus includes a substrate, a display unit arranged on the substrate, a dam unit arranged at a periphery of the display unit and on the substrate and an encapsulating layer to encapsulate the display unit, wherein the encapsulating layer includes an organic film covering the display unit, and an inorganic film covering the organic film and the dam unit, and wherein a hardness of the dam unit is lower than that of the inorganic film. According to this, lateral moisture-proof characteristics of the organic light-emitting display apparatus are improved.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.15/836,758, filed Dec. 8, 2017, which is a continuation of U.S. patentapplication Ser. No. 15/648,833, filed Jul. 13, 2017, now U.S. PatentNo. 9,842,894, which is a continuation of U.S. patent application Ser.No. 14/036,430, filed Sep. 25, 2013, now U.S. Pat. No. 9,735,223, whichclaims priority to and the benefit of Korean Patent Application No.10-2013-0040547, filed on Apr. 12, 2013, the entire contents of both ofwhich are incorporated herein by reference.

BACKGROUND 1. Field of the Invention

The present invention relates to an organic light-emitting displayapparatus and a manufacturing method thereof in which lateralmoisture-proof characteristics are improved.

2. Description of the Related Art

An organic light-emitting display apparatus includes an organiclight-emitting device including a hole injection electrode, an electroninjection electrode, and an organic light-emitting layer interposedbetween them. The organic light-emitting display apparatus is aself-emissive display apparatus where holes injected from the holeinjection electrode and electrons injected from the electron electrodeare combined to create excitons in the organic light-emitting layer, andthe excitons decay from an excited state to a ground state to emit alight beam.

Since the organic light-emitting display apparatus, which is aself-emissive display apparatus, does not need separate light sources,low voltage driving and a lightweight and thin type configuration may bepossible. The organic light-emitting display apparatus attracts theattention as a next generation display apparatus due to high definitioncharacteristics, such as wide viewing angles, high contrast, and fastresponse speeds. However, since the organic light-emitting displayapparatus is degraded by external moisture or oxygen, it is required tobe encapsulated to protect the organic light-emitting device fromexternal moisture or oxygen.

Nowadays, for a thinner and more flexible organic light-emitting displayapparatus, a thin film encapsulation (TFE) layer, including organicfilms and inorganic films, is used to encapsulate the organiclight-emitting device.

When the organic films and the inorganic films are formed, patterns areformed by disposing masks corresponding to the films on a substrate. Atthis time, an organic film may permeate a gap between the mask used toproduce the organic film pattern and the substrate. Compared to aninorganic film, the organic film has remarkably lower encapsulationcharacteristics. Therefore, when an organic film permeates a gap betweenthe substrate and the mask used to pattern the organic film, an organicfilm may be formed between the inorganic film and the substrate, orbetween the inorganic films. Also, through this, oxygen or moisture maypermeate the display unit.

SUMMARY

The present invention provides an organic light-emitting displayapparatus and a manufacturing method thereof in which lateralmoisture-proof characteristics thereof are improved.

According to one aspect of the present invention, there is provided anorganic light-emitting display apparatus that includes a substrate, adisplay unit arranged on the substrate, a dam unit arranged at aperiphery of the display unit and on the substrate and an encapsulatinglayer to encapsulate the display unit, wherein the encapsulating layerincludes an organic film covering the display unit, and an inorganicfilm covering the organic film and the dam unit, and wherein thehardness of the dam unit may be lower than that of the inorganic film.The organic film may be spaced apart from the dam unit. The dam unit mayinclude silicon, an epoxy or an acryl. The dam unit may include aplurality of dams spaced apart from each other and parallel to eachother. The dam unit may have elasticity. The organic film may includepolyurea or polyacrylate. The inorganic film may include SiN_(x), Al₂O₃,SiO₂ or TiO₂. The display apparatus may also include a lower inorganicfilm covering the display unit and the dam unit, the organic film maycover the lower inorganic film. The plurality of dams may be concentricrectangles that increase a length of a lateral path of moisture inreaching the display unit from an outside.

According to one aspect of the present invention, there is provided amethod of manufacturing an organic light-emitting display apparatus thatincludes forming a dam unit on a substrate, forming a display unitinside the dam unit and on the substrate and forming an encapsulatinglayer on the display unit to encapsulate the display unit, the formingof the encapsulating layer may include combining a mask with thesubstrate, the mask having a groove into which the dam unit is inserted,forming an organic film to cover the display unit by using the mask,separating the mask and forming an inorganic film to cover the organicfilm and the dam unit. A depth of the groove may be equal to or smallerthan a height of the dam unit, and a width of the groove may be equal toor greater than a width of the dam unit. The dam unit may includesilicon, an epoxy or an acryl. The dam unit may be produced by inkjetprinting or screen printing. The groove may have a tapered shape. Whenthe dam unit is combined to the groove, a shape of the dam unit maychange elastically according to a shape of the groove. The organic filmmay be spaced apart from the dam unit. A hardness of the dam unit may belower than that of the inorganic film. The method may also includeforming a lower inorganic film to cover the display unit and the damunit, wherein the organic film may be formed to cover a portion of thelower inorganic film, and wherein the combining the mask to thesubstrate may include inserting the dam unit covered by the lowerinorganic film into the groove of the mask.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the invention, and many of the attendantadvantages thereof, will be readily apparent as the same becomes betterunderstood by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings, in which likereference symbols indicate the same or similar components, wherein:

FIG. 1 is a side view schematically illustrating an organiclight-emitting display apparatus according to a first embodiment of thepresent invention;

FIG. 2 is an enlarged cross-sectional view illustrating a display unitof the organic light-emitting display apparatus in FIG. 1;

FIG. 3 illustrates a cross-sectional view schematically illustrating amethod of manufacturing the organic light-emitting display apparatuswhere the display unit is formed after the dam unit;

FIG. 4 illustrates a cross-sectional view schematically illustrating amethod of manufacturing the organic light-emitting display apparatuswhere the mask is attached to the dam unit of the display unit;

FIG. 5 illustrates a cross-sectional view schematically illustrating amethod of manufacturing the organic light-emitting display apparatuswhere an organic unit is formed on the display;

FIG. 6 illustrates a cross-sectional view schematically illustrating amethod of manufacturing the organic light-emitting display apparatuswhere the inorganic film is formed; and

FIG. 7 is a side view schematically illustrating an organiclight-emitting display apparatus according to a second embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

The following description with reference to the accompanying drawings isprovided to assist in a comprehensive understanding of exemplaryembodiments of the invention as defined by the claims and theirequivalents. It includes various specific details to assist in thatunderstanding, but these are to be regarded as merely exemplary.Accordingly, those of ordinary skill in the art will recognize thatvarious changes and modifications of the embodiments described hereincan be made without departing from the scope and spirit of theinvention. Also, any description that may unnecessarily blur the pointof the present invention is omitted from the detailed description.

Also, though terms like “first” and “second” are used to describevarious elements and/or portions in various embodiments of the presentinvention, the members and/or portions are not limited to these terms.These terms are used only to differentiate one member or portion fromanother one.

It will also be understood that when a portion such as a layer, a film,a region, a plate is referred to as being “on” or “above” anotherportion, it can be directly on the other portion, or intervening layersmay also be present.

Hereinafter, exemplary embodiments of the inventive concept will bedescribed in detail with reference to the accompanying drawings. In thespecification, descriptions or drawings on portions irrelative to thepresent invention will be omitted, or briefly described or drawn. Likereference numerals refer to like elements throughout. Also, in thedrawings, the thicknesses and areas of layers and regions are enlargedor exaggerated for clarity.

As used herein, the term “and/or” includes any and all combinations ofone or more of the associated listed items. Expressions such as “atleast one of,” when preceding a list of elements, modify the entire listof elements and do not modify the individual elements of the list.

Turning now to FIGS. 1 and 2, FIG. 1 is a side view schematicallyillustrating an organic light-emitting display apparatus 10 according tothe first embodiment of the present invention, and FIG. 2 is an enlargedcross-sectional view illustrating a display unit 200 of the organiclight-emitting display apparatus 10 of FIG. 1. Referring to FIGS. 1 and2, the organic light-emitting display apparatus 10 includes a substrate100, the display unit 200 formed on the substrate 100, a dam unit 120spaced-apart from the display unit 200 and on the substrate 100, and anencapsulating layer 300 encapsulating the display unit 200.

The substrate 100 may be a flexible substrate and may be made out ofplastic having excellent thermal resistance and durability, such aspolyimide, polyethylene terephthalate (PET), polycarbonate, polyethylenenaphthalate, polyarylate (PAR), and polyetherimide, however the presentinvention is not limited thereto, as the substrate 100 may instead bemade out of various other materials, such as metal or glass.

The display unit 200 may include an organic thin film transistor (TFT)layer 200 a and a pixel unit 200 b. The pixel unit 200 b may be anorganic light-emitting device. Hereinafter, the display unit 200 will bedescribed in detail with reference to FIG. 2.

A buffer layer 212 may be formed on the substrate 100. The buffer layer212 prevents impurities from permeating through the substrate 100, andprovides a flat surface on a top side of the substrate 100. The bufferlayer 212 may be made out of various materials capable of performing theabove-described functions.

For example, the buffer layer 212 may include an inorganic material,such as silicon oxide, silicon nitride, silicon oxy-nitride, aluminumoxide, aluminum nitride, titanium oxide, or titanium nitride, or anorganic material, such as polyimide, polyester, or acrylic.Alternatively, the buffer layer can be a plurality of laminated layersof organic layers and inorganic layers alternately stacked.

A TFT layer 200 a may be formed on the buffer layer 212. The TFT layer200 a may include an activation layer 221, a gate electrode 222, andsource and drain electrodes 223. Although, as an example of the TFTlayer 200 a in the present embodiment, a top gate-type TFT isillustrated, a TFT having another structure may also be included.

The activation layer 221 is made out of a semiconductor material and isarranged on the buffer layer 212, and a gate insulating film 213 isformed to cover the activation layer 221. The activation layer 221 maybe made out of an inorganic semiconductor, such as amorphous silicon orpoly-silicon, or an organic semiconductor, and have a channel regionbetween a source region and a drain region. Also, the gate insulatingfilm 213 insulates the activation layer 221 from the gate electrode 222,and may be made out of an organic material or an inorganic material,such as SiNx or SiO₂.

The gate electrode 222 is formed on the gate insulating film 213, and aninter-layer insulating film 214 is formed to cover the gate electrode222. The gate electrode 222 may include Au, Ag, Cu, Ni, Pt, Pd, Al, orMo, and an alloy, such as Al:Nd, or Mo:W alloy, but it is not limitedthereto as the gate electrode 222 may be made out of various othermaterials in consideration of design conditions. Theinter-layer-insulating film 214 is disposed between the gate electrode222 and the source and drain electrodes 223 to insulate them from eachother, and may be made out of an inorganic material, such as SiNx orSiO₂.

The source and drain electrodes 223 are formed on the inter-layerinsulating film 214. In detail, the inter-layer insulating film 214 andthe gate insulating layer 221 expose the source and drain regions of theactivation layer 221, and the source and drain electrodes 223 contactthe exposed source and drain regions of the activation layer 221.

FIG. 2 exemplifies a top gate-type TFT, which sequentially includes theactivation layer 221, the gate electrode 222, and the source and drainelectrodes 223, however the present invention is not limited thereto,and the gate electrode 222 may be disposed below the activation layer221. The above-described TFT layer 200 a is electrically connected tothe pixel unit 200 b to drive the pixel unit 200 b, and is protected bybeing covered by the planarization layer 215.

The planarization layer 215 may include an inorganic insulating filmand/or an organic insulating film. For the inorganic insulating film,SiO₂, SiN_(x), SiON, Al₂O₃, TiO₂, Ta₂O₅, HfO₂, ZrO₂, BST, or PZT may beused. For the organic insulating film, general purpose polymer (PMMA,PS), polymer derivatives having phenol-based group, acrylic-basedpolymer, imide-based polymer, aryl ether-based polymer, amide-basedpolymer, fluorine-based polymer, p-xylene-based polymer, vinylalcohol-based polymer, and a blend thereof may be used. Also, theplanarization layer 215 may be made out of a complex laminated body ofinorganic insulating films and organic insulating films.

The pixel unit 200 b is formed on the planarization layer 215, and mayinclude a pixel electrode 231, an intermediate layer 232, and anopposite electrode 233. The pixel electrode 231 is formed on theplanarization layer 215, and is electrically connected to one of thesource and drain electrodes 223 through a contact hole 230 formed in theplanarization layer 215. The pixel electrode 231 may be a reflectiveelectrode and may include a reflective film and a transparent ortranslucent electrode layer formed on the reflective film, wherein thereflective film is made out of Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr,or a compound thereof while the transparent or translucent electrodelayer may be made out of at least one or more of indium tin oxide (ITO),indium zinc oxide (IZO), zinc oxide (ZnO), indium oxide (In₂O₃), indiumgallium oxide (IGO), and aluminum zinc oxide (AZO).

The opposite electrode 233 that is opposite to the pixel electrode 231may be a transparent or translucent electrode, and may be made out of ametal thin film having small work function, which includes Li, Ca,LiF/Ca, LiF/AI, Al, Ag, Mg, and a compound thereof. Also, an auxiliaryelectrode layer or a bus electrode may be further made out of atransparent electrode-forming material, such as ITO, IZO, ZnO, or In₂O₃,on the metal thin film.

Accordingly, the opposite electrode 233 may transmit light emitted froman organic light-emitting layer included in the intermediate layer 232.That is, the light emitted from the organic light-emitting layer may bedirectly output or reflected by the pixel electrode 231 made out of areflective electrode to be output towards the opposite electrode 233.

However, the organic light-emitting display apparatus 10 according tothe present embodiment is not limited to a top-emission type, and may bea bottom-emission type where the light emitted from the organiclight-emitting layer is emitted towards the substrate 100. In this case,the pixel electrode 231 may be made out of a transparent or translucentelectrode, and the opposite electrode 233 may be made out of areflective electrode. Also, the organic light-emitting display apparatus10 according to the present embodiment may be a dual emission typeemitting light in both directions of the top and bottom surfacesthereof.

A pixel-defining film 216 is made out of an insulating material and isarranged on the pixel electrode 231. The pixel-defining film 216 exposesa predetermined region of the pixel electrode 231, and the intermediatelayer 232 is disposed on the exposed region, wherein the intermediatelayer 232 includes an organic light-emitting layer.

The organic light-emitting layer may be made out of a low molecularorganic material or a polymer organic material. The intermediate layer232 may selectively further include, besides the organic light-emittinglayer, a functional layer, such as a hole transport layer (HTL), a holeinjection layer (HIL), an electron transport layer (ETL), and anelectron injection layer (EIL).

Referring now to FIG. 1, the dam unit 120 is formed separately from thedisplay unit 200 on the substrate 100. That is, the dam unit 120surrounds a periphery of the display unit 200.

The dam unit 120, as to be described later, improves the adhesionbetween the substrate and a mask 400 (see FIG. 4) used to pattern theorganic film 310 of the encapsulating layer 300 to effectively prevent amonomer of material used to form the organic film 310 from permeating agap between the substrate 100 and the mask 400 in FIG. 4 duringformation of the organic film 310. By preventing the organic film 310from being exposed to the outside, the lateral water vapor resistance ofthe organic light-emitting display apparatus 10 is improved.

The dam unit 120 is an elastic member made out of any one of silicon, anepoxy, and an acryl. Accordingly, when combined with the mask 400 inFIG. 4, the dam unit 120 can change its shape according to a shape of agroove 410 formed in the mask 400, as shown in FIG. 4, and may thenreturn to its original shape after the mask 400 in FIG. 4 is removed.

Since the dam unit 120 exists on a periphery of the display unit 200, apermeation path of moisture or oxygen permeating the display unit 200from an external portion of the organic light-emitting display apparatus10 may be lengthened. Accordingly, the water vapor resistance of theorganic light-emitting display apparatus 10 can be further improved. Inorder to further increase water vapor resistance and although not shownin the drawings, the dam unit 120 may include a plurality of damsseparated from each other to allow a permeation path of moisture oroxygen to be further lengthened.

The encapsulating layer 300 encapsulates the display unit 200 to preventdegradation of the display unit 200. FIG. 1 exemplifies theencapsulating layer 300 including a single organic film 310 and a singleinorganic film 320, but the present invention is not limited thereto.The organic film 310 and the inorganic film 320 may instead bealternately laminated a plurality of times.

The organic film 310 is formed to cover the display unit 200, and may bespaced-apart from the dam unit 120. The organic film 310 is made out ofan organic material having flexibility, such as polyurea, orpolyacrylate to relax the internal stress of the inorganic film 320, orincrease the effect of preventing external moisture or oxygen permeationby filling minute cracks and pinholes of the inorganic film 320.

The inorganic film 320 may be made out of an inorganic material havingan excellent moisture-proof capability, such as SiN_(x), Al₂O₃, SiO₂, orTiO₂, in order to prevent external moisture or oxygen permeation.Accordingly, the inorganic film 320 is formed to cover the organic film310. Also, the inorganic film 320 is formed to cover the dam unit 120.

According to another embodiment as per the organic light-emittingdisplay apparatus 70 illustrated in FIG. 7, a lower inorganic film 340is first formed on each of substrate 100, display unit 200 and dam unit120, and then the organic film 310 and an upper inorganic film 320 maythen be sequentially formed on top of the lower inorganic film 340. Inthis case, the dam unit 120 and the substrate 100 are covered by thelower inorganic film 340 in addition to the upper inorganic film 320.

Turning now to FIGS. 3 to 6, FIGS. 3 to 6 are cross-sectional viewsschematically illustrating a method of manufacturing the organiclight-emitting display apparatus 10 in FIG. 1, according to the secondembodiment of the present invention. First, referring to FIG. 3, the damunit 120 is formed on the substrate 100, and then the display unit 200is formed inside the dam unit 120.

The dam unit 120 may be produced by an inkjet printing or a screenprinting technique. The inkjet printing is performed by printing inkcontaining a material of silicon, an epoxy, or an acryl on acorresponding portion to form the dam unit 120. The screen printing isperformed by positioning a mask (not shown) having openings incorrespondence to a position at which a dam unit is to be formed on thesubstrate 100, and then moving a squeeze rubber (not shown) in onedirection and passing a paste containing silicon, an epoxy, or an acrylthrough the openings to form the dam unit 120. Although the dam unit 120may be produced by an inkjet printing or a screen printing technique,the present invention is not limited thereto as the dam unit 120 mayinstead be produced by a coating method, such as spin coating ordepositing, and then performing a photo etching process.

After the dam unit 120 is formed, the display unit 200 is formed. Thedisplay unit 200 is formed inside the dam unit 120 to be separated fromthe dam unit 120. The display unit 200 may not only have theconfiguration exemplified in FIG. 2, but may also employ any well-knownorganic light-emitting display. Accordingly, a detailed description ofits manufacturing method is omitted.

Next, the encapsulating layer 300 is formed to encapsulate the displayunit 200. First, as shown in FIG. 4, the mask 400 is attached to thesubstrate 100, and then, as shown in FIG. 5, the organic film 310 isformed to cover the display unit 200 by using the mask 400.

The groove 410 having the dam unit 120 inserted into it is formed in themask 400. Here, the depth of the groove 410 may be equal to or smallerthan the height of the dam unit 120, and the width of the groove 410 maybe equal to or greater than the width of the dam unit 120. Here, thewidth of the groove 410 is measured on the same plane as one surface ofthe mask 400 abutting on the substrate 100, namely, a width of a portioninto which the dam unit 120 begins to be inserted. As described above,when the width of the groove 410 is equal to or greater than the widthof the dam unit 120, the dam unit 120 may be easily inserted into thegroove 410, even when an error occurs in a mask aligning process.

In addition, since the dam unit 120 has elasticity, the size and shapeof the dam unit 120 can elastically varies according to a shape of thegroove 410 when combined with the groove 410. Accordingly, since thedepth of the groove 410 is equal to or smaller than the height of thedam unit 120, the dam unit 120 ends up abutting both sides of the groove410, the result being that the mask 400 adheres to the substrate 100.

The groove 410 may have a tapered shape with a lower portion having awidth greater than an upper portion, the upper portion corresponding tothe opening of the groove 410. Due to this, the coherence between thedam unit 120 and the groove 410 is improved.

The organic film 310 is formed when the mask 400 is combined with thesubstrate 100. Since it is difficult to directly deposit a polymer, suchas polyurea or polyacrylate, which is a material of the organic film310, the organic film 310 may be formed by evaporating a liquefiedmonomer for deposition onto the substrate 100, and emitting ultravioletrays onto the deposited monomer for polymerization.

At this time, since the evaporated monomer is non-directional, if thereis a gap between the mask 400 and the substrate 100, the evaporatedmonomer may permeate the gap. However, due to combination of the groove410 and the dam unit 120 according to the present invention, the mask400 of FIG. 5 may strongly adhere to the substrate 100, and permeationof the evaporated monomer into the gap may be minimized. Accordingly,the formation of a general edge tail is prevented, and the organic film310 may be formed to be separated from and spaced apart from the damunit 120.

Even though there is a gap between the mask 400 and the substrate 100,and the evaporated monomer permeates the gap, the dam unit 120 may blockthe evaporated monomer from spreading to the periphery.

Next, as shown in FIG. 6, the mask 400 in FIG. 5 is separated from thedam unit 120 of the substrate 100, and then the inorganic film 320 isformed. The inorganic film 320 may be formed through sputtering, atomiclayer deposition, or chemical vapor deposition by using a mask (notshown) for forming the inorganic film 320.

The inorganic film 320 is formed to cover the organic film 310 and thedam unit 120. Since the inorganic film 320 is formed to cover theorganic film 310, the periphery of the organic film 310 is covered bythe inorganic film 320 that has excellent moisture-proof properties, andthe organic film 310, which is flexible but vulnerable to moisture, isnot exposed to the outside. Therefore the encapsulating layer 300 havinga very stable water vapor resistance may be realized.

In the above description of FIGS. 1 to 6, it is exemplified that theencapsulating layer 300 includes the single organic film 310 and thesingle inorganic film 320, however, the present invention is not limitedthereto, as the encapsulating layer 300 may instead include a pluralityof the organic films 310 and a plurality of inorganic film 320alternately laminated. Also, in the second embodiment of FIG. 7, theencapsulating layer 300 of the organic light-emitting apparatus 70 mayinstead include a lower inorganic film 340 being first formed, and anorganic film 310 and an upper inorganic film 320 being sequentiallyformed on the lower inorganic film 340 and still be within the scope ofthe present invention. In the second embodiment of FIG. 7, the dam unit120 is formed on the substrate 100 and is covered by the lower inorganicfilm 340 as well as the upper inorganic film 320.

According to the embodiments of the present invention, lateralmoisture-proof characteristics of an organic light-emitting displayapparatus can be improved by preventing an organic film from permeatinga gap between a mask and a substrate during formation of the organicfilm.

While the present invention has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit and scopeof the present invention as defined by the following claims.

What is claimed is:
 1. An organic light-emitting display apparatus,comprising: a substrate; a display unit arranged on the substrate; a damunit around a periphery of the display unit and on the substrate; afirst inorganic film covering the display unit and the dam unit; a firstorganic film covering a portion of the first inorganic film; and asecond inorganic film covering the organic film and the dam unit;wherein the first organic film covers an entirety of the display unit,wherein the dam unit is arranged at a periphery of the first organicfilm, wherein the first organic film covers an upper surface and sidesurfaces of the display unit, and wherein the first organic film isbetween the first inorganic film and the second inorganic film.
 2. Theorganic light-emitting display apparatus of claim 1, wherein the damunit comprises a material selected from the group consisting ofsilicone, an epoxy, and an acryl, wherein the dam unit has elasticityand is adapted to change its shape according to a shape of a groove of amask that attaches to the dam unit.
 3. The organic light-emittingdisplay apparatus of claim 1, wherein the second inorganic filmcomprises a material selected from the group consisting of SiN_(x),Al₂O₃, SiO₂, and TiO₂, the second inorganic film being vacuum depositedand having a non-planar upper surface.
 4. The organic light-emittingdisplay apparatus of claim 1, the first inorganic film covers anentirety of opposing sidewalls of the dam unit.
 5. An organiclight-emitting display apparatus, comprising: a substrate; a displayunit arranged on the substrate; a dam unit around a periphery of thedisplay unit and on the substrate; a first inorganic film covering thedisplay unit and the dam unit; a first organic film covering a portionof the first inorganic film, wherein the first organic film entirelycovers the display unit; and a second inorganic film covering theorganic film and the dam unit, wherein the dam unit is arranged at aperiphery of the first organic film, wherein the first organic filmcovers an upper surface and side surfaces of the display unit, andwherein the first organic film is between the first inorganic film andthe second inorganic film.
 6. The organic light emitting display deviceof claim 5, wherein an upper surface of the second inorganic film thatfaces away from the substrate is non-planar due to the underlyingdisplay unit and the dam unit, wherein a distance from the substrate tothe second inorganic film in a direction normal to an upper surface ofthe substrate varies with location.
 7. The organic light emittingdisplay device of claim 5, the first organic film comprising at leastone of polyurea and polyacrylate.
 8. An organic light-emitting displayapparatus, comprising: a flexible substrate; a buffer layer on theflexible substrate; a display unit arranged on the buffer layer; a damunit directly contacting the buffer layer; a first inorganic filmcovering the display unit and the dam unit and directly contacting thebuffer layer; a first organic film covering a portion of the lowerinorganic film; and a second inorganic film covering the organic filmand the dam unit, wherein the first organic film covers an entirety ofthe display unit, and wherein the first organic film is between thefirst inorganic film and the second inorganic film.
 9. The organiclight-emitting display apparatus of claim 8, wherein the secondinorganic film comprises a material selected from the group consistingof SiNx, Al₂O₃, SiO₂, and TiO₂, the second inorganic film being vacuumdeposited and having a non-planar upper surface.
 10. The organiclight-emitting display apparatus of claim 9, wherein the first inorganicfilm covers an entirety of opposing sidewalls of the dam unit.
 11. Theorganic light-emitting display apparatus of claim 10, wherein the secondinorganic film directly contacts a portion of the first inorganic filmbetween the display unit and the dam unit.